Mouth and throat problems

Radiation therapy is often used to treat cancers in the mouth, throat, neck or upper chest region. Depending on the area treated, radiation therapy may affect your mouth and teeth. This can make eating and swallowing difficult, and change your sense of taste.

Learn more about:

• Taste and swallowing changes
• Dry mouth and other issues
• Teeth problems
• How to relieve mouth and throat problems

Taste and swallowing changes

You may have thick phlegm in your throat, or a lump-like feeling that makes it hard to swallow. Food may also taste different. Normal taste usually returns in time. Sometimes, swallowing may be affected for months after treatment, but it is rare for problems to be permanent.

For more on this, see Mouth health and cancer treatment and Taste and smell changes.

Dry mouth and other issues

After treatment, your mouth or throat may become dry and sore, and your voice may become hoarse. Radiation therapy can cause your salivary glands to make less saliva, which can contribute to a dry mouth. These effects will gradually get better after treatment finishes, but it may take several weeks or even months. In some cases, the effects may improve but not completely disappear.

Dry mouth (xerostomia) can make chewing, swallowing and talking difficult. A dry mouth can also make it harder to keep your teeth and mouth clean, which can increase the risk of tooth decay.

Teeth problems

Radiation therapy to the mouth may increase the chance of tooth decay or other problems in the future. You will need to have a thorough dental check-up and may need to have any decaying teeth removed before treatment starts.

Your dentist can provide an oral health care plan with instructions on caring for your teeth and dealing with side effects such as mouth sores. You will need regular dental check-ups after treatment ends to prevent any problems in the future.

How to relieve mouth and throat problems

• Have a dental check-up before you start treatment. Ask for a referral to a dentist who specialises in the effect of radiation therapy on teeth.
• Keep your mouth moist by sucking on ice chips, mints and sipping cool drinks. Carry a bottle of water with you.
• Ask your doctor, nurse or pharmacist for information about artificial saliva to moisten your mouth.
• Chew sugar-free gum to help the flow of saliva.
• If you have a dry mouth, you may need to avoid rough, crunchy or dry foods (e.g. chips, nuts, toast, dry biscuits); salty or spicy foods that sting your mouth; or very hot or cold food.
• Avoid smoking, drinking alcohol or caffeinated drinks, and having citrus or tangy tomato-based food and juice. These things will irritate your mouth and make dryness worse.
• Ask your doctor for a referral to a speech pathologist. They can suggest ways to modify the texture of foods so they are easier to swallow.
• If chewing and swallowing are painful, drink liquids using a straw or eat soft or minced textured foods.
• Ask a dietitian for suggestions on meals and snacks to try, or see Nutrition and Cancer for ideas.
• To manage taste changes, add more flavour to food (e.g. add lemon juice to meat and vegetables, marinate foods, use herbs and spices).
• Talk to your doctor if eating is uncomfortable or difficult. If you are in pain, ask them about pain medicine to help with swallowing.
• Rinse your mouth often – when you wake up, after you eat or drink, and at bedtime. Ask your doctor or nurse what type of alcohol-free mouthwash to use and how often to use it. They may give you an easy recipe for a homemade mouthwash.